In the contact form manager/XYZ WP Contact Form we are using html table structure for the form.
At present there is no specific style for the form and it is using the default style of your theme.
If you want to reduce the spacing between 2 fields, either you can modify your style.css file of your theme or add a style for the <td> tag.
The present default format is given below.
To change the spacing, please change this format to
<td style="height:25px">Your Name</td>